The present invention relates to valves used in high pressure applications, and particularly, a leak detector for such a valve.
In the injection of polyurethane products, high pressure and temperature of liquid chemicals are selectively supplied to a plurality of mixing chambers and subsequently injected into molds. It is important that the chemicals be supplied to a selected mixing chamber in a controlled fashion and only when the injection process is taking place. Valves such as ball valves have been inserted into series with the chemical flow path between the high pressure source and a mixing chamber. These valves are self-opening at a relatively high pressure such as 1,500 psi for allowing chemical to be introduced into a desired mixing chamber at a high pressure with the remaining valves closed to prevent undesired seepage of chemicals into conduits leading to other mixing chambers of a typical multiple head installation.
As the seats of such valves tend to wear, chemicals can seep through the valve seats and the loss of chemicals can cause an improper ratio of chemicals supplied to a mixing head resulting in faulty parts. Even a small amount of leakage through a valve can cause shut-down of an injection molding facility for repair and the loss of many parts before the problem is discovered. Naturally, as the valves wear, frequently the first indication of such wear is the failure of valuable parts.